The present invention relates to a magnetic head device wherein a magnetic head can be precisely set in a predetermined direction with respect to a magnetic recording medium and a pressure pad can be precisely set in a predetermined direction so as to bring the magnetic recording medium into close contact with the magnetic head.
High density recording has recently been demanded in magnetic recording techniques. For this reason, perpendicular magnetic recording is receiving a great deal of attention as opposed to conventional longitudinal-direction magnetic recording. In a perpendicular magnetic recording system, the magnetic medium is magnetized in a direction perpendicular to its surface, thereby achieving high density recording. However, as the density of the recorded signals is increased, their wavelengths are shortened (i.e., the frequency of the signal increases), so that the recording and reproduction characteristics are highly sensitive to and greatly influenced by the spacing between the magnetic head and the recording medium. In order to obtain good recording and reproduction characteristics, the predetermined positional relationships of the magnetic head and the magnetic recording medium must be established with high precision. However, with the conventional magnetic head device, proper sliding contact between the recording medium and the magnetic head cannot be achieved.
FIGS. 1 and 2 show conventional magnetic head devices. A floppy disc 1 as a recording medium is rotated by a rotary support unit 2. The floppy disc 1 is mounted on a spindle 3 of the rotary support unit 2 such that a hole 1a at the center of the floppy disc 1 is aligned with a rotating shaft of the rotary support unit 2. The floppy disc 1 is rotated by a motor (not shown) together with the spindle 3 through a belt 4. A magnetic head 5 is fixed on a support table 6. An L-shaped member 7 is fixed on the support table 6. A support plate 9 is mounted on the L-shaped member 7 through an elastic portion 9a such that one end of the elastic portion 9a is fixed on the side wall of the L-shaped member 7 and the other end thereof is fixed on the support plate 9. A pressure pad 8 is fixed on the lower surface of the support plate 9 so as to oppose the magnetic head 5 through the floppy disc 1. The pressure pad 8 biases the floppy disc 1 toward the magnetic head 5 via a coil spring 9b. The coil spring 9b is mounted between the inner surface of the upper wall of the L-shaped member 7 and the upper surface of the support plate 9. In the conventional magnetic head device, the sliding contact between the magnetic head 5 and the floppy disc 1 cannot be properly attained. Furthermore, often due to misalignment of the pressure pad center and the head gap center, the sliding contact between the pressure pad 8 and the floppy disc 1 cannot be adjusted, so that the pressure pad 8 cannot bias the floppy disc 1 toward the head gap of the magnetic head 5 with a constant, uniform pressure.
In the perpendicular magnetic recording system, a magnetic recording medium may be used which comprises a base layer such as a polyester film and a cobalt-chromium alloy layer sputtered on the base layer. The magnetic recording medium of this type has high rigidity and may not be properly brought into close contact with a tape guide surface of the magnetic head. For these reasons, a space tends to be formed between the recording medium and the tape guide surface of the magnetic head. Therefore, the sliding contact between the magnetic head 5 and the floppy disc 1 cannot be properly kept when the pressure pad 8 fixed to the support plate 9 is used. As a result, good recording and reproduction characteristics cannot be obtained. Furthermore, when the magnetic head 5 wears out, it cannot be readily replaced with a new one.
On the other hand, among audio magnetic head devices, there is a magnetic head device, as shown in FIG. 2, in which the position of a magnetic head 5 can be adjusted. The magnetic head 5 is mounted on a support plate 10. Screws 11 are mounted to adjust the level of the support plate 10 with respect to a support table 6. Coil springs 12 are respectively mounted on the screws 11 between the support table 6 and the support plate 10, so that the support plate 10 and hence, the magnetic head 5 are biased upward. As a result, an operator can turn the screws 11 to adjust the distance between the support plate 10 and the support table 6. However, according to the adjustment mechanism of this type, the head position cannot be adjusted with high precision with respect to the floppy disc 1. Furthermore, this adjustment mechanism is rather large and cannot be installed in a compact floppy disc recording/reproduction apparatus.
Briefly, in conventional magnetic head devices, sliding contact between the recording medium and the pressure pad, and between the recording medium and the magnetic head, cannot be precisely achieved. If such a magnetic head device is applied to a perpendicular magnetic recording system, good recording and reproduction characteristics cannot be obtained.